As can be seen on the charts above, Nokia is clearly much further along in the transition from its old Symbian platform to Windows Phone. The bad news, however, is that Lumia shipments currently total only about a quarter of Nokia’s smartphone shipments three years ago. BlackBerry isn’t quite as far along with BB10, having shipped just 2.7 million BlackBerry 10 smartphones last quarter compared to a quarterly peak of about 14 million units just two years ago.

Both companies face a steep uphill climb as they struggle to compete with Apple, which now has about 400 million active iOS devices in use, and Google, which has activated more than 800 million Android devices to date.